RIO DE JANEIRO, May 27 (Reuters) - Petrobras' new chief

executive said a basin in Brazil's Equatorial Margin, an

environmentally sensitive offshore prospect seen as the

country's most promising frontier for oil exploration, was a

matter of "national interest."

Magda Chambriard, who took over as the state-controlled oil

company's chief executive after President Luiz Inacio Lula da

Silva fired its former CEO this month, said on Monday she wanted

to escalate talks about the region near Guyana to the National

Council of Energy Policy (CNPE), which advises the president.

In her first public comments since taking the company's

helm on Friday, Chambriard said replenishing oil reserves was a

priority for Petrobras, and that exploring the Equatorial Margin

was part of that effort.

Petrobras has been waiting for about a year for Brazil's

environmental agency Ibama to rule on an appeal made by the firm

after the agency denied it the license to drill in the

Equatorial Margin's Foz do Amazonas basin over concerns about

the impact it could have on the environment and Indigenous

peoples. It is about 175 km (109 miles) off the coast of the

state of Amapa, in the Amazon region.

The offshore basin is seen as a potential bonanza because it

shares geology with nearby Guyana, where Exxon Mobil ( XOM ) is

developing huge fields.

Chambriard said discussions on whether or not to explore

the promising new oil frontier should not be left to one single

government body, without specifying whether she meant Ibama, the

environment ministry or some other organization.

"I think that every time we restrict a discussion to a

single institution, and do not expand this discussion to

national interests, we lose," Chambriard said.

The discussion on whether or not to explore the region must

be held taking into account the benefits it could bring to

Brazilian society, she said.

Chambriard noted that the president would be the one to sign

off on any deliberation by the CNPE.

"Every deliberation of the National Council of Energy Policy

is signed by the president."

Chambriard also said Petrobras would maintain its current

pricing policies for gasoline and diesel sales, stressing that

the company had to be profitable while also meeting shareholder

needs.

Chambriard said she intended to maintain the adjustments to

the company's motor fuel pricing strategy made by the prior

management team.

Petrobras implemented last year a more market-based fuel

pricing policy for gasoline and diesel sales to favor greater

flexibility while avoiding drastic price swings.

Chambriard, a former head of oil and gas regulator ANP,

vowed to better insulate the company's fuel prices from

international market volatility.